Many species of sunscreening agents are employed in the cosmetic art to prevent harmful effects of the sun on the hair and skin or to prevent deterioration of the active agent from UV exposure. However, most sunscreens are easily removed by water or perspiration so that repeated application is needed. While aromatic, water insoluble sun blocks are more resistant to removal, they do not have a high degree of skin, hair or plant substantivity and their incorporation in water based formulations is difficult.
Certain types of polymers exhibit film-forming characteristics and, when dissolved in a suitable solvent, can be applied for the purpose of providing a durable coating on a substrate. Usually, the film-forming polymer solution is applied to a particular substrate and the solvent is allowed to evaporate leaving a film of the polymer. However, such film-forming polymers are generally soluble only in organic solvents which are undesirable for cosmetic and agricultural uses since they possess environmentally adverse properties and are often flammable or otherwise hazardous. Furthermore, the cost of these solvents demands recovery in order to achieve economical operation; however their recovery is not easily realized, usually involving rather complicated and time consuming procedures.
Accordingly, it is an object of this invention to provide an economical and durable sunscreening composition which is non-toxic and has no environmentally adverse affect.
Another object of this invention is to provide a sunscreening concentrate which is readily incorporated into standard cosmetic and agricultural formulations.
Still another object is to provide an oil-in-water emulsion of the present sunscreen composition which is easily combined with cosmetic or agrichemical emulsions or dispersions for their stabilization against the harmful effects of UV light.
Yet another object of this invention is to provide a sunscreening composition in the form of a water-dispersible powder.